package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {
    /**
     * BEGIN_TIMESTAMP:开始时间戳
     * COUNT_BITS:位运算位移位数
     */
    private final long BEGIN_TIMESTAMP = 1739955360L;  //加L表示Long类型
    private final int COUNT_BITS = 32;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    /**
     * @param keyPrefix:区分不同业务的前缀
     * @return
     */
    public long nextId(String keyPrefix) {
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSeconds = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSeconds - BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1 获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2自增长
        Long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //3.拼接并返回
        return timestamp << COUNT_BITS | count;
    }
}
